I got a check light on and they told me it needed a purge soleniod on 1999 Audi A6 Quattro

hello I got a 99 audi a6 Quattro, I got a check light coming on, they told me it is the purge solenoid, once it is install how do I reset the computer to get the check light off?

Asked by for the 1999 Audi A6 Quattro
unhook the battery for 10 minutes